The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Navigation systems that automatically route drivers, bicyclists and pedestrians between geographic locations generally utilize indications of distance, street names, building numbers, etc. to generate navigation instructions based on the route. For example, these systems can provide to a driver such instructions as “proceed for one-fourth of a mile, then turn right onto Maple Street.” To users who are en route to a destination, a portable component of the navigation system can provide relative navigation instructions, i.e., instructions that are based on the direction of the movement. Examples of such navigation instructions include “turn left onto Main Street.” However, at the beginning of navigation, when the user is stationary and there is no direction of movement yet, the navigation systems in general provide absolute directions such as “go North on State Street.” Users can find absolute directions difficult to use, as they do not always know their orientation. However, it is difficult for a portable device to determine its operation or heading while the portable device is at rest.